Process of making soap



Patented May i399 will grigia JRQCESS @F MAKEN@ S@ Benjamin H. Thurman, Erona'N. Y., assigner to Benning, lne., Reno, Nev., a corporation ci* Nevada Application March 5, l, Serial No. New@ (Gli E-Jll) l@ @Halma lt is an objectoi' the invention to provide av novel process oi making anhydrous soap.

Another object of the invention is to provide a process of making soap in which powdered alkali is employed. l

Another object or the invention is to provide a process of making soap in which powdered anhydrous alkali is caused to react directly with saponinable materials containing combinedA vol= atiles to form anhydrous soap and liberate said volatiles in recoverable form.

Another object of the invention is to provide a process of making soap in which water is solom stantially absent from the process and substantially pure and anhydrous glycerine is continuously recovered.

A further object of the invention is to providev a continuous process of caus'ng molten anhy drous caustic alkali to react with glycerol esters of higher fatty acids to form anhydrous soap and liberate anhydrous glycerine.

A still further object of the invention is to provide a continuous processl in which fatty materials consisting essentially of glycerides oi fatty acids are caused to react with anhydrous caustic soda to produce anhydrous soap separately from anhydrous glycerine Other objects and advantages of the invention will .appear in the following description oi a preferred embodiment o the invention made in connection with the attached drawing, which is a diagrammatic view of an apparatus capable of carrying out the process.

Referring more particularly to the drawing,

l@ and il indicate mixing. devices ier mixing proper proportions or" dry powdered alkali with a saponiiable material; li? and i3 indicate heatm ing devices for the mixture prepared inthe mixers ill and il; lil indicates a vapor separating chamber for separating volatile materials from anhydrous soap produced in the process; it and it indicate a condenser and receiver, refspectively, :for the volatile materials, and l@ indicates a vacuum pump for maintainin vac uum in the vapor separating chamber The mixing devices i@ and ii may b with agitators il driven, for exampl pulley it rotated from any suitable source or power. The mixers l@ and il are also pref erably provided with heating devices such as a heating jacket i9 through which any suitable heating medium, for example steam, can be circulated by the pipes 2@ and 2l so as to mainn tain the saponinable material or mixture thereof with the powdered alkali in the ilowable condition. The mixing devices l@ and il are intended to be used alternatively in preparing mix tures or" saponiable material, for example :glyceride oils or higher fatty acid estersoi higher fatty alcohols, with anhydrous powdered alkali such as caustic soda. Thus, by closing the valve .22 in the pipe 23 and opening the valve 2li in the pipe 25, such a mixture may be pumped from the mixer ll by means of the pump 2t while a mixture isbeing prepared in the mixing device The pump 2t is utilized to force the mixture Athrough. a heating device l2, shown as a coil 2l,

heated by a burner 23 on gaseous or liquid fuel. To reach the high temperatures contemplated by the present invention, it is usually necessary to employ one or more supplemental heating de-1 vices it which may be exactly similar to the heating device lli and include a coil il' and a burner 2t. A pump te is preferably associated with each heating device it to force the mixture therethrough. Such pumps also have a valuable mixing function byltending to keep the mixture uniform. Y

The temperature in the heating vdevice lil is raised suillciently high to cause reaction between the powdered alkali and the saponiable material to form soap and liberate 'any alcohol form7 ing part or the saponifiable material. The ternperature in the coil la is usually sumciently high to vaporize all or a substantial part of the alcohol or other vaporizable material and render the soap molten, such that a mixture containing moltenvsoap and vapors is delivered into the vapor separating chamber it through the pipe it. The mixture is preferably discharged against the wall 3i of the vapor separating chamber by nozzles 32 directed toward the Wall di. This i wall is. preferably maintained in a heated condi=l tion by a heating jacket 33 surrounding the vapor separating chamber ld. A suitable heating ine- `diurn such as, for example, heated mineral oil is l circulated through the heating jacket 33 by the pipes tl and t5 so as to maintain the wall 3i above the melting point of the anhydrous soap rroduced. This temperature will vary between approximately 450 F. and 620 F., depending upon the type of vsaponifialcie material and alkali employed. The iuid mixture discharged from the. nozzles 32 iiows down the Wall 3l in thin lms, thus providing for rapid evaporation of i are collected in the receiver i6, from which they i may be periodically or continuously withdrawn Athrough a pipe Il by any suitable means, suchas a pump. A vacuum, which is preferably as high as commercially practicable, for example 27 vto 29 inches of mercury, is maintained in the receiver I6, condenser I5 and vapor. separating chamber Il by means of the vacuum pump It'.

The molten soap from which volatile materials have been removed ilows into the housing of a screw conveyor indicated at Il, which conveyor is provided with a cooling `iaclret 3l for, cooling and solidifying the molten soap. 'I'he conveyor 38' continuously removes 'the .anhydrous soap from the vapor separating chamber I I while maintaining a vacuum seal for this chamber, and cools 'the soap to a temperature at whichthe soap will not be injured by contactwith the atmosphere. The vapor separating chamber Il and conveyor y38 may be of the type disclosed in the copending application of Benjamin Clayton and Benjamin H. Thurman, Serial No. 119,168; led January 5, 1937, which .application discloses the structure of the vapor separating chamber and conveyor system in detail.

Anhydrous caustic alkalies, for example caus- 'and I3 in series with pumps positioned therebetween in order to reduce the pressure necessary to be developed by a single pump forcing the mixture through a heating device or devices of suiilcient capacity to reach the desired temperature. Also, the booster pumps, such as pump 29, aid in maintaining the mixture substantially uniform.

tic soda, do not. react appreciably with such saponiiiable materials as glyceride oils or other es. ters of higher fatty acids, for example sperm oil, at temperatures below approximatelyl 350\ F.

4Dry anhydrous caustic soda may, therefore, be mixed with such saponiilable materials without appreciable reaction at room temperature or at any temperature necessary to cause the oil to be in a freely owable condition. It is preferred to preheat the saponiable material in the mixers I0 and il to approximately 140 to 200 F. during mixing of the powdered caustic therewith, so as to cut down the amount oi heat necessary to be added subsequently in the process, and to render the mixture easily pumpable.

The proportions of the alkali to saponiflable material should be such as to produce a substantially neutral soap, and will vary with the saponication number of the material being saponied. That is, for an oil having a saponincation num-f ber of 190, the mixture will consist of one pound of saponiflable material to 0.136 pound of dry anhydrous sodium hydroxide. 'Ihis produces, a mixture in which the disposed solid is only 13.6% of the saponiilable material, and such a mixture can readily be pumped through the heating de'- vice 2.

By alternatively supplying the process with materials from one ofthe mixers and mixing saponiilable material and alkali in the other mixer, the necessary proportions to produce a'substantially neutral soap can be easily attained and substantially uniform mixtures prepared and maintained by the agitators l1. 'I'he agitators l1 are rotated during the pumping of the material from the mixers l0 and Ii' as well as during initial mixing in order to maintain the mixture substantially uniform, and also the' pump V26 serves to additionally dispose the alkali'in the oil. A colloid mill (not shown) 4may be employed, if found necessary, but extremely finelyy Substantial saponiilcation begins in the neighborhood of 350 F., a-t which time any soap produced is suiilciently plastic to be ilowable along with the mixture of saponiilable material and alkali. This is important, as -the formation of anhydrous soap at a temperature much below that mentioned would cause a stliiening oi the mixture such that extremely high pressures would be necessary to force the same through the heating devices. In order to insure complete saponiilcation of the saponiilablematerial, it is preferred to raise the temperature of the mixture above the melting point of the alkali employed. Caustic soda melts at 604 F., and it is therefore desirable to reach a temperature of approximately 610 to 625 F. before the resulting mix.

ture oi anhydrous soap and volatile materials is delivered -into the evaporating chamber when caustic soda is employed. Caustic'potash does not melt until a temperature of 716 F. has been reached and temperatures between 716 and 735 F, are within the contemplation of the present invention when employing caustic potash, although employment of caustic soda is preferred in the, present process, primarily because ofi-the' lower temperatures possible.

Since soap does not begin to form until relatively high temperatures have been reached, the process may be carried on at pressures not substantially in excess of 300 pounds per square inch, and in many cases pressures of to 150 pounds per square inch can be employed. It is preferred to performthe process with as low pressures as practical. It will be appreciated that the pressure will be highest adjacent the entrance to the heating coils 21, and will progressively drop throughout the heating coils and that, therefore, the pressure will be the lowest in the rglon of highest temperature in any of the coils 1.

I It is also preferred to operate the process so4 that all ofthe volatile material, such as glycerine or higher fatty alcohols, is in vapor form when contained heat of the materials entering the vapor separating chamber. In order to secure the formation of vapors in at least the last heating device, the discharge pressure thereof should be aaaaiar relatively low, for example 30 to 10G pounds per square inch. f

If the saponiable material is comprised of esters of higher fatty acids, the glycerine or other alcohol separated from the soap in the vapor separating chamber it and condensed in the condenser l5 will be anhydrous and substantially pure. Any free fatty acids present in the saponiable material will result in the liberation -of water during the saponication reaction, thus somewhat diluting the materials condensed in the condenser l5. This is not of material importance with higher fatty acid esters of higher fatty alcohols,-as the condensed'higher fatty alcohols are immiscible with water and canbe easily separated therefrom.

, However, when saponifying glycerides the presence of free fatty acids in the saponifiable material will result in a glycerine mixture containing dissolved water, although', with any mixn saponiflable material must, however, not be excessive, as the dry anhydrous caustic reacts with the free fatty acids at relatively low temperatures forming soap and'small amounts of water. Thus, large proportions of free fatty acids will cause plastic or solid soap to form before the temperature has become sufficiently high to render the soap owable. A small percentage of free fatty acids, for example up to 5%, can be present, however, in the saponiable material.

Also, a relatively small proportion of an inert liquid, for example kerosene, can be added to the material in the mixers it and Il to maintain the mixture flowable until high temperatures have been reached, even if greater amounts of free fatty acids are present. Such liquid will be sepradicals to liberate hydrogen and form soap containing saturated fatty acid radicals having a lesser number of carbon atoms than the carbon atoms of the original unsaturated fatty acid radicals. The Varrentrapp reaction is a time-consuming reaction, and may-be largely avoided in the present process by rapidly raising they temperature above the melting point of the powdered anhydrous caustic alkali and then immediately separating the volatiles from the resulting soap cooling the soap thus formed. Since the caustic alkali in the present invention is employed in substantially chemically equivalent quantities with the saponifiable material, an excess ofl caustic is not present to accelerate the Varrentrapp reaction.

The Varrentrapp reaction is not necessarily undesirable, as it reduces the unsaturation of the fatty acid radicals of the resultant soap, thus increasing the stability` of the soap. A harder and better wearing soap is also produced. 'By varying the amount of time the anhydrous soap mixture is maintained at high temperatures necessary to complete the reaction, the extent to which the Varrentrapp reaction takes place can be Varied. 'Ilhus soap of varying characteristics can be prol in the vapor separating chamber ld and quickly duced by the present process by prolonging the time of treatment at the high temperatures contemplated. Any hydrogen produced is removed from the system by means of the vacuum pump Since the anhydrous mixture of saponifiable material and caustic, and also the resulting mixture of soap and volatile materials, are maintained out of contact with the atmosphere and in motion throughout the entire process, no local overheating or pyrolytic decomposition vof the various materials is produced. Any volatile impurities are removed from the soap, thus producing a light colored substantially pure soap from any reasonably pure saponifiable material.

The process nds its chief utility in the saponification of glyceride oils and fats, since substantially pure glycerine in anhydrous form is directly recovered as part of the continuous process of making soap. However, the process also finds utility with other esters of fatty acids, for example, higher fatty acids of higher fatty` alcohols such as sperm oil and wool grease.

While I have disclosed the preferred embodiments of this invention, it is understood that the details thereof may be4 varied within the scope of the following claims.

I claim as my invention:

1. The process of producing soap and recovering glycerine, which comprises, mixing substantially anhydrous powdered alkali with a glyceride oil substantially free of uncombined fatty acids, heating a owing stream of said mixture to a temperature at least as high as the melting point of said alkali and above the melting point of the soap when anhydrous to produce soap and liberate glycerine, and thereafter delivering said stream into a vapo-r separating zone Iand separating said glycerine in substantially anhydrous vapor form from said soap to produce substantially anhydrous moltenl soap.

2. The process of producing soap and separating volatile `materials therefrom, which comprises, mixing a saponif-lable material substantially free of uncombined fatty acids with anhydrous caustic alkali, heating a flowing stream of said mixture to a temperature above the melting point of said alkali so as to produce substantially anhydrous molten soap and form vapors of volatile materials contained in said saponifiable materials, delivering said stream into a vapor separating zone and separating said volatile materials in vapor form from saidl soap in the absence of substantial amounts of water vapor to produce substantially anhydrous molten soap.

3. The process of producing substantially anhydrous soap, which comprises', mixing substantially anhydrous powdered caustic soda With a glycerol ester of a higher fatty acid substantially free of uncombined fatty acids, heating a flowing stream of the resulting mixture out of contact with the atmosphereto a temperature sufficiently high to cause said caustic soda to react with said ester to produce anhydrous molten soap and glycerine vapors, and thereafter delivering ,raid stream into a vapor separating zone, separating glycerine vapors in the absence of substantial quantities of water vapor from said soap under vacuum conditions and condensing said glycerine vapors to assist in maintaining said vacuum and to produce substantially anhydrous liquid glycerine.

4. The process of producing soap, which comprises, mixing a saponifiable material consisting essentially of esters of higher fattyacids substantially free of uncombined fattv acids with measured proportions oi substantially anhydrous powdered caustic alkali, heating a Ilowing stream of said mixture out of contact with the atmosphere to a temperature above the melting point suillcient to maintain said vacuum, and removing.

and cooling said soap before discharging the n same into the' atmosphere.

5. The process oi' producing soap, which comprises, mixing substantially anhydrous powdered' caustic alkali with a liquid saponilable material substantially free of uncombined fatty acids and which will not react with said alkali at relatively low temperatures, heating a ilowing stream of said mixture while substantially free of water to a temperature suiiiciently high to cause said saponiiiable material to react with said Valkali to form molten soap, and cooling a stream of said soap to a relatively low temperature before discharging the same -to the atmosphere.

6'; The process of producing soap and separating volatile materials therefrom, which comprises, mixing a saponiable material containing combined volatile material and substantially i'ree of uncombined fatty acids with anhydrous powdered caustic soda, forming a stream of said mixture, heating said stream to a temperature between approximately 604 F. and 625 F. so as to produce soap and form vapors of said volatile materials substantially free of water vapor, and separating said vapors from said soap.

'1. The process pf producing soap, which comprises, mixing substantially anhydrous caustic alkali with a saponiilable material substantially free of uncombined fatty acids, and heating a flowing stream of said mixture in the absence ot v substantial quantities of water to a'temperature at least as high as the melting point of said alkali to cause said alkali to react with said saponiable material to produce substantially anhydrous molten soap.

8f The process of producing soap, which comprises, mixing substantially anhydrous powdered caustic alkali with a saponiable material su'bstantially free of uncombined fatty acids, heating a flowing stream of `said mixture in the absence `of substantial quantities of water out of contact with the atmosphere to a temperature at least as high as the melting point of said alkali to cause said alkali to react with said saponifiable material to produce substantially anhydrous molten soap.

9. The process of producing soap, which comprises, mixing substantially anhydrous powdered alkali with a saponiiable material substantially free of uncombined fatty acids, heating a iiowing stream of said mixture in the absence of substantial quantities of water and out of contact lwith the atmosphere to a temperature sumciently high to cause said powdered alkali to react with said saponiflable material to produce substantially anhydrous molten soap.

10. The process of producing soap, which comprises, mixing substantially anhydrous powdered caustic alkali with a saponiable material submolten. soap.

e BENJAMIN H. THURMAN. 

